Ethanol from biomass by enzymatic hydrolysis
Enzymes are biological catalysts that generally are designed to do one job well, but to do one job only. Therefore, the enzymes that catalyze the hydrolysis of cellulose to sugar do not break down the sugars. Thus, enzymatic processes are capable of yields approaching 100%. Enzymatic hydrolysis processes have been under development for only 10 years. Although improvements have been made in enzymatic technology, more are both possible and necessary. The important research issues include understanding the processes necessary to render the crystalline cellulose easily digestible, understanding and improving the basic mechanisms in the hydrolysis step, and developing better and less expensive enzymes. The hemicellulose fraction (25%) is primarily composed of xylan, which is simple to convert to the simple sugar xylose, but the xylose is difficult to ferment to ethanol. There were no practical systems for xylose fermentation 10 years ago. Today, methods have been identified using new yeasts, fungi, bacteria, and processes combining enzymes and yeasts. Although none of the fermentations is yet ready for commercial use, considerable progress has been made. The following sections describe current research efforts in each of the major areas (cellulose hydrolysis, xylose fermentation, and lignin conversion), with an emphasis on enzymatic hydrolysis using fungal enzymes.
- Research Organization:
- Solar Energy Research Institute, Golden, CO (US)
- OSTI ID:
- 6943966
- Journal Information:
- Chem. Eng. Prog.; (United States), Vol. 84:8
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
54 ENVIRONMENTAL SCIENCES
10 SYNTHETIC FUELS
BIOMASS
ENZYMATIC HYDROLYSIS
CELLULOSE
FERMENTATION
ETHANOL
BIOSYNTHESIS
LIGNIN
ENERGY CONVERSION
POLYMERS
XYLOSE
BACTERIA
BIOTECHNOLOGY
CATALYSTS
CATALYTIC EFFECTS
CHEMICAL REACTION KINETICS
ENERGY CONSERVATION
OCTANE
PHENOLS
RESEARCH PROGRAMS
TECHNOLOGY ASSESSMENT
YEASTS
ALCOHOLS
ALDEHYDES
ALKANES
AROMATICS
BIOCONVERSION
CARBOHYDRATES
CHEMICAL REACTIONS
CONVERSION
DECOMPOSITION
ENERGY SOURCES
FUNGI
HYDROCARBONS
HYDROLYSIS
HYDROXY COMPOUNDS
KINETICS
LYSIS
MICROORGANISMS
MONOSACCHARIDES
ORGANIC COMPOUNDS
PENTOSES
PLANTS
POLYSACCHARIDES
REACTION KINETICS
RENEWABLE ENERGY SOURCES
SACCHARIDES
SOLVOLYSIS
SYNTHESIS
090222* - Alcohol Fuels- Preparation from Wastes or Biomass- (1976-1989)
140504 - Solar Energy Conversion- Biomass Production & Conversion- (-1989)
500200 - Environment
Atmospheric- Chemicals Monitoring & Transport- (-1989)
090400 - Solid Waste & Wood Fuels- (-1989)
090600 - Gaseous Waste Fuels- (-1989)